Value

A data.frame with pollution data measured in IMECAs, by geographic
zone. The hours correspond to the Etc/GMT+6 timezone, with no
daylight saving time

Details

Note that in 2015 it was determined that the stations with codes ACO, AJU,
INN, MON and MPA would no longer be taken into consideration when computing
the pollution index because they didn't meet the
objectives
of monitoring air quality. They are no longer included in the index, even if
they are still part of the SIMAT (Sistema de Monitoreo Atmosférico de la
Ciudad de México). Thus, even if they are located inside a zone, they are not
included in the pollution values for that zone.